The present invention relates to containers for solid materials having liquids associated therewith, e.g., such materials as liquid-laden fruits, vegetables, household waste, fresh meat or seafoods, and yard waste, such as grass clippings. The above materials are known to provide the basis for desirable composting substrates. Thus, the present invention provides a fully, and rapidly, biodegradable container suitable for composting, and related purposes.
It is useful for our purposes to note that Nature disposes of millions of tons of plant debris each year, with the main constituent of plant tissue being cellulose. The present invention, therefore, has utilized a material made from cellulose, called, herein, cellulose film, or cellophane, which is fully biodegradable, just as leaves and plants are, to become the basis of the herein-described fully biodegradable container, suitable for all composting purposes.
Cellulose, along with sugars and starches, belongs to a group of chemical compounds known as carbohydrates. Carbohydrates contain only carbon, hydrogen, and oxygen, and are the ultimate source of most of the foods that we eat.
The backbone of cellulose is the glucose molecule. In trees, for example, this glucose molecule is accompanied by smaller and larger sugars, as well as lignin, all of which make up the vascular structure we see as wood. The glucose, or glucan, molecules form long chains which are the building blocks of fibers. More specifically, cellulose film, or cellophane, is made from regenerated cellulose, which no longer contains lignins, and long fiber chains.
Micro-organisms, such as fungi and bacteria, typically found in soil, and elsewhere, break down the cellular walls of the glucose molecules and digest them. A material is considered biodegradable if it is capable of being decomposed, or compostible, by natural biological processes. Consequently, this process of micro-organisms breaking down and digesting the cellular walls in cellulose film, or cellophane, allows the cellulose film, or cellophane, material to completely biodegrade.
This same activity occurs with trees and plants. The primary difference is the time it takes to biodegrade. Trees and plants take much longer to biodegrade than cellulose, because the lignins and long molecular fiber chains in these materials are more difficult to biologically break down.
It is known that solid materials having a significant liquid content can be carried in waterproof containers, i.e., bags or sacks, having liquid impervious liners therein. In some cases, the bag or sack can be formed from a two-ply sheet material, comprising an outer layer of paper and a non-biodegradable inner layer of wax, or a liquid-impervious plastic film-material, such as polyethylene, polyvinyl chloride, polyethylene terephthalate, oriented polypropylene, or the like.
One major problem with such bag-like containers is that they are not adequately biodegradable when they are either littered, or later placed in landfills. In an ever-increasingly environmentally conscious world, there is now a strong need for a bag-like container that is both liquid impervious, and at the same time, completely or fully, and rapidly biodegradable.
A further requirement is that the bag-like container should have a mouth construction that is both sealable and unsealable with minimum effort. Thus, odor-producing liquid-containing materials can be placed into the container at spaced time intervals, e.g., once or twice per day, until the container is at least substantially filled. Further, the bag-like container construction should be such that odors are substantially trapped within the container during standby periods, between each placement of material into the container, and the next placement of material into the container.
A further requirement is that the bag-like container should be manufacturable at relatively low cost. Preferably, the materials used to make the bag should be relatively low cost materials, that are also readily available in reasonably large quantities, whereby the bag can be mass-produced at low cost in a range of different sizes.
As a related matter, it is also desirable that the bag-like containers be manufacturable with existing machines and apparatus, i.e., apparatus that is already in use for manufacturing conventional bag-like containers.
Another desirable feature would be a bag-like container that is self-sustaining, or self-standing, i.e., a bag construction that will stand by itself on a floor, or shelf, in an open condition, ready for placement of moist or wet solid materials therein. Also, the bag should have a relatively high wet strength, so that it can hold a reasonably large amount of wet solids without bursting, leaking, or disintegrating.